Partially resorbable implants and methods

ABSTRACT

Implants including non-resorbable frameworks and resorbable components, as well as methods of use thereof are disclosed. The embodiments include different combinations of a non-resorbable framework (in some case structural and in other cases non-structural), and a resorbable component embedded within and/or around the framework (again, in some cases structural and in other cases non-structural). The disclosed implants provide an efficient means of providing structural support for the vertebral bodies post-implantation, as well as encouraging resorption of the implant and fusion of the associated vertebral bodies without negative side effects and/or failure, such as subsidence of the implant or cracking/fracturing of a portion of the implant when implanted.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of the filing date of U.S. Ser. No.62/163,146 (“the '146 Provisional”), filed May 18, 2015, the disclosureof which is incorporated by reference herein.

BACKGROUND OF THE INVENTION

The present invention relates to spinal surgery, namely the fusion ofadjacent intervertebral bodies or the replacement of a vertebral body.

Back pain can be caused by many different maladies, not the least ofwhich are problems that directly impact the intervertebral discs of thespine. Typical disc issues include, inter alia, degeneration, bulging,herniation, thinning, abnormal movement, spondylosis, spinal stenosis,disc herniation, retrolisthesis, and discogenic back pain. One method oftreatment of such disc problems that is widely utilized in the field ofspinal surgery is a spinal fusion procedure, whereby an affected disc isremoved, and the adjacent vertebral bodies are fused together throughthe use of interbody spacers, implants, or the like. In some instances,it may also be necessary to remove and replace an entire vertebral body.This is often accomplished through the use of a larger implant that actsto fuse together the vertebral bodies adjacent the removed vertebralbody.

In replacing a diseased intervertebral disc(s) and affecting fusion, itmay also be necessary to ensure that proper spacing is maintainedbetween the vertebral bodies. It is also the case that an implant mustbe structured to effectively support and bear the post-surgical loadsinherent in movement of the adjacent vertebral bodies of the spine afterimplantation. At the same time, proper and effective fusion of thevertebral bodies is of concern. Thus, implants exist in which resorbablematerials are used to promote fusion, but in many cases these implantsare not structurally sound or are susceptible to failure in one way oranother. As an example, allograft spacers constitute a resorbablematerial, but such spacers are often brittle during implantation and canfracture. Other drawbacks to existing resorbable implants also exist.

Therefore, there exists a need for an improved spinal implant.

BRIEF SUMMARY OF THE INVENTION

A first aspect of the invention includes an implant sized and adaptedfor insertion into an intervertebral space between adjacent vertebralbodies. The implant comprises a non-resorbable, structural frameworkhaving top and bottom bone-contacting surfaces and a plurality of strutsdefining geometric openings between the top and bottom surfaces, thestruts providing structural support for the framework, wherein theframework includes a plurality of support columns extending betweenproximal and distal ends of the framework, the plurality of supportcolumns being spaced apart from each other to define vertical openingsin the framework. The implant also includes a resorbable materialcomponent within and/or around the framework for resorption andformation of new bone to fuse the vertebral bodies together. In certainembodiments of this first aspect, the resorbable material component is astructural component that includes top and bottom bone-contactingsurfaces configured to support post-surgical loads experienced afterimplantation of the implant.

A second aspect of the invention includes an implant sized and adaptedfor insertion into an intervertebral space between adjacent vertebralbodies. The implant comprises a non-resorbable, non-structural frameworkhaving top and bottom bone-contacting surfaces formed of a porousmaterial, and a resorbable, structural component positioned between thetop and bottom surfaces of the framework to provide structural supportfor the top and bottom surfaces and the implant. In an embodiment ofthis second aspect, the top and bottom surfaces of the framework are twomillimeters (2 mm) or less in thickness.

A third aspect of the invention includes an implant sized and adaptedfor insertion into an intervertebral space between adjacent vertebralbodies. The implant comprises a non-structural, non-resorbable frameworkhaving a main body and a fluid conduit within the main body, the mainbody having an injection port in fluid communication with the fluidconduit. The implant also includes a resorbable, structural componenthaving top and bottom bone-contacting surfaces and an opening in atleast one of the top and bottom surfaces, the opening being in fluidcommunication with the fluid conduit. In an embodiment of this thirdaspect, a fluid conduit projects outward from the main body and isfluidly connected with the fluid conduit in the main body, wherein theoutwardly-projecting fluid conduit defines the opening in the at leastone of the top and bottom surfaces of the resorbable, structuralcomponent.

A fourth aspect of the invention includes an implant sized and adaptedfor insertion into an intervertebral space between adjacent vertebralbodies. The implant comprises a non-structural, non-resorbable frameworkhaving a series of ring members connected together by way of a pluralityof struts, and a resorbable, structural component embedded with and/oraround the framework for encouraging resorption of the implant andfusion of the vertebral bodies. In an embodiment of this fourth aspect,the ring members are arranged transverse to a longitudinal axis of theframework, and the struts extend along the longitudinal axis and connectthe ring members.

A fifth aspect of the invention includes a method of reducing subsidenceof an implant into bone. The method comprises providing an implanthaving a non-resorbable structural framework and a resorbable structuralcomponent positioned within and/or around the framework. The frameworkis implanted between first and second adjacent vertebral bodies so thattop and bottom surfaces of the framework contact vertebral endplates ofthe first and second vertebral bodies, and the resorbable component islikewise implanted between the first and second adjacent vertebralbodies so that top and bottom surfaces of the resorbable componentcontact the vertebral endplates. Once implanted, the top and bottomsurfaces of the resorbable component contact the vertebral endplatesover a contact surface area sufficient to reduce peak stresses betweenthe framework and the vertebral bodies by an amount effective toeliminate or reduce subsidence of the framework into the vertebralbodies. In an embodiment of this fifth aspect, in the absence of theresorbable component, peak stresses between the framework and thevertebral bodies is above a stress required for the vertebral endplatesto fail, for example above 160 MPa.

A sixth aspect of the invention includes an implant sized and adaptedfor insertion into an intervertebral space between adjacent vertebralbodies. The implant comprises a non-resorbable, structural frameworkhaving top and bottom bone-contacting surfaces and a plurality of strutsdefining geometric openings between the top and bottom surfaces, thestruts providing structural support for the framework. The implant alsoincludes a resorbable material component within and/or around theframework for resorption and formation of new bone to fuse the vertebralbodies together, wherein the resorbable material has top and bottombone-contacting surfaces, and the top and bottom surfaces of theresorbable component are arranged to contact the vertebral endplatesover a contact surface area sufficient to reduce peak stresses betweenthe framework and the vertebral bodies by an amount effective to reduceor eliminate subsidence of the framework into the vertebral bodies. Inan embodiment, the contact surface area is between about 30-70% of anoverall contact surface area of the implant in contact with thevertebral endplates. In another embodiment, in the absence of theresorbable component, peak stresses between the framework and thevertebral bodies is above a stress required for the vertebral endplatesto fail.

BRIEF DESCRIPTION OF THE DRAWINGS

The patent or application file contains at least one drawing executed incolor. Copies of this patent or patent application publication withcolor drawing(s) will be provided by the Office upon request and paymentof the necessary fee.

A more complete appreciation of the subject matter of the presentinvention and of the various advantages thereof can be realized byreference to the following detailed description in which reference ismade to the accompanying drawings in which:

FIGS. 1A-E are perspective (1A), proximal (1B), top (1C), distal (1D),and side (1E) assembled views of an implant having a non-resorbable,structural framework and a resorbable component positioned within and/oraround the framework, in accordance with an embodiment of the presentinvention.

FIGS. 2A-E are perspective (2A), proximal (2B), top (2C), distal (2D),and side (2E) views of the non-resorbable, structural framework of theimplant of FIGS. 1A-E.

FIGS. 3A-E are perspective (3A), proximal (3B), top (3C), distal (3D),and side (3E) views of the resorbable component of the implant of FIGS.1A-E.

FIGS. 4A-E are perspective (4A), proximal (4B), top (4C), distal (4D),and side (4E) assembled views of an implant having a non-resorbable,structural framework and a resorbable component positioned within and/oraround the framework, in accordance with another embodiment of thepresent invention.

FIGS. 5A-E are perspective (5A), proximal (5B), top (5C), distal (5D),and side (5E) views of the non-resorbable, structural framework of theimplant of FIGS. 4A-E.

FIGS. 6A-E are perspective (6A), proximal (6B), top (6C), distal (6D),and side (6E) views of the resorbable component of the implant of FIGS.4A-E.

FIG. 7 is a Finite Element Analysis of the structural framework of theimplant of FIGS. 1A-E.

FIGS. 8A-E are perspective (8A), proximal (8B), top (8C), side (8D), andcross-sectional (8E) assembled views of an implant having a porous,non-resorbable, non-structural framework and a resorbable, structuralcomponent positioned within and/or around the framework, in accordancewith yet another embodiment of the present invention.

FIGS. 9A-E are perspective (9A), proximal (9B), top (9C), side (9D), andcross-sectional (9E) views of the framework of the implant of FIGS.8A-E.

FIGS. 10A-E are perspective (10A), proximal (10B), top (10C), side(10D), and cross-sectional (10E) views of the resorbable, structuralcomponent of the implant of FIGS. 8A-E.

FIGS. 11A-E are perspective (11A), proximal (11B), top (11C), side(11D), and cross-sectional (11E) assembled views of an implant having anon-resorbable framework with fluid channels and a resorbable,structural component positioned within and/or around the framework, inaccordance with yet another embodiment of the present invention.

FIGS. 12A-E are perspective (12A), proximal (12B), top (12C), side(12D), and cross-sectional (12E) views of the non-resorbable frameworkof the implant of FIGS. 11A-E.

FIGS. 13A-E are perspective (13A), proximal (13B), top (13C), side(13D), and cross-sectional (13E) views of the resorbable, structuralcomponent of the implant of FIGS. 11A-E.

FIGS. 14A-E are perspective (14A), proximal (14B), top (14C), side(14D), and cross-sectional (14E) assembled views of an implant having anon-structural, non-resorbable framework and a resorbable, structuralcomponent positioned within and/or around the framework, in accordancewith yet another embodiment of the present invention.

FIGS. 15A-E are perspective (15A), proximal (15B), top (15C), side(15D), and cross-sectional (15E) views of the non-structural,non-resorbable framework of the implant of FIGS. 14A-E.

FIGS. 16A-E are perspective (16A), proximal (16B), top (16C), side(16D), and cross-sectional (16E) views of the resorbable, structuralcomponent of the implant of FIGS. 11A-E.

FIGS. 17-18 are Finite Element Analyses of the implant of FIGS. 14A-E.

FIG. 19 is a perspective view of a prototype embodying thenon-resorbable, structural framework of the implant of FIGS. 1A-E.

FIG. 20 is a perspective view of a prototype embodying thenon-resorbable, structural framework of the implant of FIGS. 4A-E.

FIG. 21 is a perspective view of a prototype embodying the porous,non-resorbable framework of the implant of FIGS. 8A-E.

FIG. 22 is a perspective view of a prototype embodying thenon-resorbable framework of the implant of FIGS. 11A-E.

FIG. 23 is a perspective view of several prototypes embodying thenon-structural, non-resorbable framework of the implant of FIGS. 14A-E.

FIG. 24 is a Finite Element Analysis of a certain load being applied tothe implant of FIGS. 1A-E, with the framework and resorbable componentused therewith.

FIG. 25 is a Finite Element analysis of a certain load being appliedonly to the framework of FIGS. 2A-E, without the resorbable component ofFIGS. 3A-E.

DETAILED DESCRIPTION

In describing the preferred embodiments of the invention illustrated andto be described with respect to the drawings, specific terminology willbe used for the sake of clarity. However, the invention is not intendedto be limited to any specific terms used herein, and it is to beunderstood that each specific term includes all technical equivalents,which operate in a similar manner to accomplish a similar purpose.

As used herein, the term “structural” means the ability to bear thepost-operative service load without the need for a second material. Theterm “structural” is not restricted to the ability to bear the entirepost-operative service load, and may include bearing some (e.g., atherapeutically effective amount) or a majority of the post-operativeservice load.

The present invention includes a variety of implants that have anon-resorbable framework or skeleton, in certain cases providingstructural support and in other cases being non-structural, incombination with a resorbable component or material that is embeddedwithin and/or around the framework. The resorbable component providesstructural support in some cases or is non-structural in others. Theparticular combination of a non-resorbable framework along with aresorbable component or material, as disclosed herein, allows an implantto adequately support adjacent vertebral bodies when implanted during afusion process while also encouraging positive bone formation andresorption of the implant.

Referring to FIGS. 1A-E, an implant 10 is shown that has anon-resorbable structural framework 20 and a resorbablecomponent/material 50 embedded within framework 20. Framework 20provides structural support for implant 10, while resorbable material 50encourages or allows for bone formation and fusion for adjacentvertebral bodies contacting implant 10.

Framework 20 is shown in detail in FIGS. 2A-E. Framework 20 includes topand bottom bone-contacting surfaces 22, 24, proximal and distal ends 40,42, and teeth 26 formed on top and bottom surfaces 22, 24. In somecases, framework 20 is formed through an additive manufacturing process,such as selective laser melting (SLM), selective laser sintering (SLS),3D printing, or any other additive process. Through the additive process(or by using another manufacturing method), framework 20 is created toinclude a network of struts 28 that define a variety ofdifferently-shaped geometric openings 30. Indeed, the body of framework20 may be successively composed layer-by-layer through an additiveprocess, as detailed above, so that struts 28 are formed to define thedifferent geometric openings 30 of framework 20. In an embodiment,geometric openings 30 are present along the sides of framework 20, atproximal and distal ends 40, 42, and along a series of support columns32 of framework 20. Thus, geometric openings 30 can provide access toand throughout an interior of framework 20 so that bone growth can occurinto framework 20, as described in more detail below.

Support columns 32 of framework 20 each include various struts 28defining geometric openings 30, which act to provide structural supportfor framework 20. In an embodiment, framework 20 is designed to bear asubstantial portion (e.g., fifty percent (50%) or more) of theanticipated post-surgical load for implant 10. Support columns 32 alsoeach include portions of top and bottom bone-contacting surfaces 22, 24of framework 20, which have teeth 26. Struts 28 support such portions oftop and bottom bone-contacting surfaces 22, 24. Support columns 32 alsodefine vertical openings 34 in framework 32, which may provide areas forresorbable material 50 to extend between.

As shown in FIGS. 2A-B and 2E, respectively, framework 20 also includesan opening 36 (optionally threaded) at its proximal end 40 forattachment with an implantation tool (not shown), as well as a bulletednose 84 at its distal end 42 to ease implantation of implant 10 into adisc space between adjacent vertebral bodies.

In an exemplary embodiment, framework 20 is composed of titanium ortitanium alloy (porous or solid), tantalum, stainless steel,polyetheretherketone (PEEK), polyetherketoneketone (PEKK), or a materialdeveloped by the Applicant, which is referred to as Cortoss®.Combinations of the foregoing materials may also be used. Non-resorbableframework 20 can also incorporate osteoconductive materials, resorbablecoatings, or resorbable materials within voids or pores of thenon-resorbable material to make framework 20 an active participant inthe fusion process. As an example, framework 20 may be constructed ofsolid and porous portions, as described in Applicant's U.S. PatentApplication Ser. No. 62/103,276, filed Jan. 14, 2015, now U.S. patentapplication Ser. No. 14/994,749, which are hereby incorporated byreference herein. The '276 application was attached as Exhibit A to the'146 Provisional. As set forth therein, in particular embodiments, theteeth of certain implants can be formed from porous and solidstructures. Such teeth could be incorporated into framework 20, or usedwith any other implant described in more detail below. Additionally, the'276 application describes other implant structures with porous andsolid features, and it is contemplated that such technology may be usedwith framework 20, or any other framework or implant discussed morefully below.

In an embodiment, top and bottom surfaces 22, 24 of framework 20 arealso tapered towards one another by a degree sufficient to accommodatethe natural lordosis that may exist between the adjacent vertebralbodies. Such lordosis exists, for example, between adjacent vertebralbodies in the lumbar spine. Other embodiments, however, may includeparallel top and bottom surfaces 22, 24.

Resorbable component/material 50 is shown in FIGS. 3A-E. In anembodiment, resorbable material 50 comprises a flowable/curable materialthat is embedded within and/or around framework 20. Resorbable material50 may also provide structural support for implant 10 by defining topand bottom surfaces 52, 54 that are arranged to contact adjacentvertebral bodies, in addition to top and bottom surfaces 22, 24 offramework 20, and support the vertebral bodies once implant 10 isimplanted. Indeed, as shown in FIGS. 1A-E, once material 50 is embeddedwithin framework 20, it fills in the space between certain supportcolumns 32 and provides top and bottom surfaces 52, 54 that are arrangedto contact adjacent vertebral bodies. Further, top and bottom surfaces52, 54 include teeth 62 for digging into the vertebral bodies. In anembodiment, top and bottom surfaces 52, 54 are also tapered towards oneanother by a degree sufficient to accommodate the natural lordosis thatmay exist between the adjacent vertebral bodies, but can also bearranged parallel.

Resorbable material/component 50 also includes a single vertical opening60 that, when combined with framework 20, provides a vertical opening 60in implant 10. Vertical opening 60 may receive, for example, a bonegraft material to further enhance the resorptive characteristics ofimplant 10 and promote fusion.

In an exemplary embodiment, resorbable material 50 is composed ofbioactive glass, bone, polylactides, collagen, magnesium alloy, or aCross-Linked Microstructure (CLM) bioglass material developed by Bio2Technologies, Inc. as described, for instance, in Bio2 Technologies'U.S. Pat. No. 8,673,016, which is hereby incorporated by referenceherein. Combinations of the foregoing materials may also be used.Resorbable material 50 may include one of the materials above in acollagen or other polymeric carrier to facilitate molding into framework20. A template manufacturing process may also be used in which calciumphosphate, sol-gel derived bioactive glass, or another ceramic isproduced on a porous template which occupies the openings withinframework 20, and is then sacrificed by heat treatment so that only theceramic is left behind. It may also be desirable to fill framework 20with a powder, particulate, or fiber form of resorbable material 50 in amold and then further process by heat, chemical cross-linking or othermeans to bond or sinter the powder, particulate, or fibers into a solidor porous final state which fills framework 20.

In one case, resorbable material 50 may comprise a majority of theoverall material volume of implant 10, for example fifty percent (50%)or more of the overall volume. Resorbable material 50 may be embeddedwithin struts 28. In addition, although resorbable material 50 isdescribed above as providing structural support for implant 10, in analternate embodiment resorbable material is non-structural dependingupon the intended implementation for implant 10. For example, anon-structural resorbable component 50 may be useful for applications inwhich loading is expected to be predictable or additional resistance tosubsidence into bone is not required. A structural resorbable component50 may be required to add surface area to reduce local contact pressurewhere implant 10 contacts bone for configurations in which structuralframework 20 is not adequate to prevent subsidence or other failure ofthe bone, despite framework 20 having the necessary strength towithstand the service load. In either case, the combination ofresorbable component 50 and framework 20 results in a greater fusionmass than what a traditional PEEK or titanium cage would allow, as amajority of implant 10's volume becomes resorbed and replaced by bone.

In another embodiment, non-resorbable framework 20 may be composed of aradiopaque material, and the particular arrangement of framework 20 mayoptimize visualization of the resulting fusion mass within or around theimplant. For instance, as shown in the side view of FIG. 1E, framework20, in particular struts 28 thereof, define geometric openings 30 ofroughly a diamond shape within an otherwise radiopaque structure, whichallows for viewing the resulting fusion mass using standard imagingtechniques from a lateral perspective. Moreover, the minimal amount ofradiopaque material in this area, as well as the extent of geometricopenings 30, provide direct visualization of resorbable component 50under visualization. Generally, with prior art devices, the fusion masswould be occluded from a lateral perspective due to the presence of aradiopaque structure(s) blocking visualization of the mass.

FIG. 7 shows a Finite Element Analysis of framework 20 demonstrating thepost-operative loads that framework 20 can withstand. The Finite ElementAnalysis illustrates a load of 10,000 Newtons being applied to framework20, and the subsequent stresses seen in framework 20. As illustrated,framework 20 can withstand the 10,000 Newton load (or greater) withoutyielding. A load of 10,000 N was selected as it is representative of atypical dynamic service load.

FIG. 25 shows another Finite Element Analysis of framework 20 (withoutresorbable component 50) in which the scale of the Finite ElementAnalysis is different than in FIG. 7. In FIG. 25, the scale is set toone-hundred and sixty megapascals (160 MPa), as that is the typicalfailure point for bone. Thus, the Finite Element Analysis of FIG. 25illustrates the stresses created on framework 20 upon application of10,000 N load, within a scale of one-hundred and sixty megapascals (160MPa), to thereby illustrate where bone failure might occur anywherealong framework 20. As shown, certain areas of framework 20, illustratedin red, approach or exceed stresses of 160 MPa when a 10,000 N load isapplied. Thus, at these areas, without resorbable component 50 and thesupport it provides for implant 10, there would likely be failure ofvertebral bone and subsidence of framework 20 into the bone. In otherwords, these areas of high local stress on framework 20 (withoutresorbable component 50) would ordinarily result in framework 20subsiding into the vertebral bodies.

As seen in FIG. 24, however, which is a Finite Element Analysis ofimplant 10 (i.e., framework 20 with resorbable component 50), resorbablecomponent 50 acts to distribute loads across the extent of implant 10and thereby reduce the risk of subsidence. As shown, no areas on the topof implant 10 approach or exceed 160 MPa (the failure point for bone).Instead, maximum stresses across implant 10 appear to be on the order ofabout 60-80 MPa, and in an embodiment are 75 MPa. For the Finite ElementAnalyses of FIGS. 24-25, framework 20 was constructed as a scaffold ofTi6Al4V, having a Young's Modulus of about 104,800 MPa and Poison'sRatio of 0.3, while resorbable component was composed of a biologicmaterial having a Young's Modulus of 4.1 GPa and Poison's Ratio of 0.25.

In a particular implementation of implant 10, the surface area ofnon-resorbable framework 20 may be about fifty percent (50%) of thesurface area of the entire implant 10, while the surface area ofresorbable component 50 may also be about fifty percent (50%). Further,the overall volume occupied by framework 20 may be about thirty percent(30%) of the volume of implant 10, while the overall volume ofresorbable component 50 may be about seventy percent (70%). In thisconfiguration, the 50%/50% surface area ratio results in a 68% reductionin the peak stress that the device imparts to the vertebral bodyendplate when a 10,000 N load is applied, which results in a stress (75MPa) safely below the yield strength of bone (160 MPa). In the absenceof resorbable component 50, the resulting stress to the vertebralendplate caused by framework 20 is about 237 MPa, which is well abovethe yield strength of bone and would be likely to result in unwantedsubsidence of framework 20. Thus, the particular combination offramework 20 and resorbable component 50 acts to decrease subsidence ofimplant 10 and encourage or allow bone formation and fusion to occur.

Implant 10 may be implanted into a disc space between adjacent vertebralbodies or as part of a corpectomy procedure in the same fashion as atraditional interbody device (IBD) or vertebral body replacement (VBR),respectively. Implant 10 allows for fusion to occur as resorbablematerial 50 is resorbed and replaced by newly-formed bone.Non-resorbable framework 20 acts as a structural scaffold or as aframework for resorbable material 50 to interface with. Thenon-resorbable framework 20 that contacts the vertebral end plates canalso act to help the fusion process by, for example, beingosteoconductive and/or incorporating resorbable coatings or resorbablematerials within voids or pores of the non-resorbable material, etc., asdescribed above. The particular configuration of resorbable andnon-resorbable material in implant 10 therefore efficiently achievesfusion and bone formation, while providing ample structural support foradjacent vertebral bodies.

A particular manufacturing technique may also be used to constructimplant 10 of FIGS. 1A-E (or any of the other implants, discussedbelow). In an embodiment, polycaprolactone (PCL) is dissolved in GlacialAcetic Acid (GAA) at room temperature until homogenous. Bioactive glassis then added to the PCL-GAA solution under light agitation to preventsettling. Once thoroughly mixed, the solution is loaded into a syringeand extruded into a mold containing framework 20. The filled mold isthen injected with water and/or completely submerged in a water bath toprecipitate the plastic onto the device. Once all of the PCL hasprecipitated, the filled implant 10 is removed from the mold.

Referring to FIGS. 4A-E, an alternate implant 110 is shown that issimilar to implant 10. Due to the similarities between implants 10, 110,like numerals (within the 100-series of numbers) refer to like elementsin this embodiment and predominantly the differences between theembodiments will be discussed herein.

Implant 110 includes a structural, non-resorbable framework 120 and aresorbable component/material 150 positioned within and/or aroundframework 120. As shown in FIGS. 5A-E, framework 120 is similar toframework 20 of implant 10, except that it includes left 137, center138, and right 139 sections and a keyed opening 144 between thesections. Keyed openings 144 are formed along top and bottom surfaces122, 124 and extend from proximal end 140 to distal end 142 of framework120. In a particular embodiment, a first keyed opening 144 is positionedalong top surface 122 between left 137 and center 138 sections, a secondkeyed opening 144 is positioned along top surface 122 between center 138and right 139 sections, a third keyed opening 144 is positioned alongbottom surface 124 between left 137 and center 138 sections, and afourth keyed opening 144 is positioned along bottom surface 124 betweencenter 138 and right 139 sections. Thus, a total of four (4) keyedopenings 144 may be present in an embodiment.

Keyed openings 144 are shaped and arranged to receive a variety ofarrow-shaped bone anchors as disclosed, for example, in Applicant's U.S.Pat. No. 8,349,015, which is hereby incorporated by reference herein. Anexample of an arrow-shaped bone anchor is shown in FIGS. 4A-E as anchor174. An anchor very similar to anchor 174 is shown and described inconnection with FIGS. 6A-B of the '015 patent, and it is expresslycontemplated that anchor 174 may include any of the features of theanchor of FIGS. 6A-B of the '015 patent, or any other anchor disclosedin the '015 patent. Thus, anchor 174, for example and not by way oflimitation, can include an interconnection portion 176 extending from ananchor portion 178 for engaging with keyed openings 144. Interconnectionportion 176 may be dovetail-shaped in an embodiment to engage with adovetail-shaped opening 144 in framework 120. Further, although notshown herein, as described in the '015 patent anchor 174 may have a stopfeature at its trailing end to ensure that anchor 174 does not traveltoo far into framework 120. Anchor 174 may also have lock features forlocking anchor 174 into engagement with framework 120 once fullyinserted. Put simply, anchor 174 can include any of the features of anyof the anchors of the '015 patent, and engage and be retained inframework 120 by the means described in the '015 patent. Anchor 174 cantherefore provide an efficient means of securing implant 110 to adjacentvertebral bodies once implanted.

As shown in the particular implementation of anchor 174 in FIGS. 4A-E,anchors 174 may be arranged to diverge and angle away from one anotheralong top and bottom surfaces 122, 124 of framework 120, and thusimplant 110. However, any of the directional and/or angledconfigurations of anchors disclosed in the '015 patent could equally beused with framework 120, and thus implant 110.

Framework 120 also differs from framework 20 in that it is substantiallydevoid of struts and geometric openings, as present in framework 20.Instead, vertical openings 134 are defined in top and bottom surfaces122, 124 of left 137, center 138, and right 139 sections of framework120, and lateral openings 148 are present as well. Further, framework120 may be open between each support column 132 within the main body offramework 120.

Resorbable component 150 is shown in detail in FIGS. 6A-E. As resorbablecomponent 150 is somewhat similar to resorbable component 50, likenumerals refer to like elements in this embodiment and predominantly thedifferences between components 50, 150 will be discussed herein.Resorbable component 150 includes left 168, center 170, and right 172sections to match left 137, center 138, and right 139 sections offramework 120. Resorbable component 150 may be composed of a flowablematerial that is positioned within and/or around framework 120 during,for example, manufacturing. Alternatively, it may be possible topre-construct resorbable component 150 and slide it into engagement withframework 120 through an opening in framework 120 (e.g., one of lateralopenings 148). Each of left 168, center 170, and right 172 sections ofresorbable component 150 include a vertical opening 160 that isalignable with vertical openings 134 of framework 120. Thus, onceresorbable component 150 is positioned within and/or around framework120, vertical openings 160 of resorbable component 150 define openingsin implant 110 that, in an embodiment, are sized to receive bone-graftmaterial (e.g., for promoting fusion).

Resorbable component 150 also includes its own keyed openings 166 foraligning with keyed openings 144 of framework 120 and providing aninterconnection mechanism between implant 110 and anchors 174. In aparticular embodiment, a first keyed opening 166 is positioned along topsurface 152 of resorbable component 150 between left 168 and center 170sections, a second keyed opening 166 is positioned along top surface 152between center 170 and right 172 sections, a third keyed opening 166 ispositioned along bottom surface 154 of resorbable component 150 betweenleft 168 and center 170 sections, and a fourth keyed opening 166 ispositioned along bottom surface 154 between center 170 and right 172sections. Keyed openings 166, like keyed openings 144, may be of anyshape, have any direction and/or angle, and include any of the featuresof such similar keyed openings as described in the '015 patent,incorporated by reference above. Thus, keyed openings 166 engage withanchors 174 once resorbable component 150 is positioned within and/oraround framework 120.

Resorbable component 150 may also include engagement structures 164, forexample in the form of cutouts, arranged to engage with like engagementstructures (not shown) in framework 120. Such engagement structures 164secure resorbable component 150 to framework 120. Resorbable component150 also includes an opening 180 for connection with an insertion toolthat is alignable with like opening 136 in framework 120. Openings 136,180 are, in an embodiment, threaded for engagement with a threadedportion of an implantation tool.

Although certain structures of framework 120 and/or resorbable component150 are not discussed above, for example teeth 126, 162 thereon, it isto be understood that such structures are encompassed in framework 120and/or resorbable component 150 and are referenced in the figures by wayof reference numerals that correspond or are like the reference numeralsfor framework 20 and resorbable component 50 of implant 10.Additionally, it is to be understood that any of the materials disclosedfor framework 20 and resorbable component 50 may be used to composeframework 120 and resorbable component 150, and that resorbablecomponent can be used as a structural member in an embodiment or anon-structural member in other embodiments. When used as a structuralmember, resorbable component 150 can act to assist with preventing ormitigating subsidence of framework 120 into adjacent vertebral bodies, acommon downfall of current PEEK and/or titanium cages. Further, thesurface area and volume percentages and ratios discussed above inconnection with implant 10 can also be used with implant 110.

Some beneficial aspects of implants 10, 110 above include but are notlimited to: (1) the addition of a resorbable component 50, 150 that may,at least initially, act to distribute contact loads with bone in orderto prevent failure of the bone due to high localized stresses(subsidence is a known potential failure mode of existing IBDs); (2) aparticular balance of resorbable and non-resorbable structures that bothmeets overall implant structural requirements and results in minimizingthe volume, location, and orientation of radiopaque non-resorbablestructures to facilitate the use of radiographic imaging techniques toassess local anatomy and progress of a fusion mass; and/or (3) acombination of resorbable and non-resorbable regions able to interfacewith additional fixation elements in such a manner that fixation betweenthe IBD and bone is not lost as material resorbs. Other benefits ofimplants 10, 110 are clearly also experienced.

FIGS. 8A-E depict another implant 210, according to an embodiment of thepresent invention. Implant 210 includes a substantially non-structural,non-resorbable frame 220 used in connection with a structural,resorbable component 250 positioned within frame 220. In thisembodiment, certain like reference numerals refer to like elements but,due to the difference between implant 210 and implants 10, 110, noconsistent numbering scheme is used.

Frame 220, as shown in FIGS. 9A-E, includes top and bottombone-contacting surfaces 222, 224 that, in an embodiment, are formed ofa porous but non-resorbable material. Top and bottom surfaces 222, 224may be very thin in some instances (e.g., two millimeters (2 mm) orless), and thus, top and bottom surfaces 222, 224 alone arenon-structural due to their thinness. Yet, when combined with structuralresorbable component 250, implant 210 is able to meet the demands of thepost-surgical loads that are typically experienced while alsoencouraging fusion and resorption.

Frame 220 also includes proximal and distal ends 240, 242 and an opening236 for connection with an implantation tool (not shown) at proximal end240. Opening 236 is threaded in an embodiment to engage with a threadedportion of an implantation tool (not shown). Frame 220 has a bulletednose 238 at its distal end 242, and a vertical opening 226 through frame220's top and bottom surfaces 222, 224. Frame 220 also includes a largelateral opening 228 sized to receive resorbable component 250, asdescribed below. An opposing lateral side of frame 220 is closed, asshown in cross section in FIG. 9E.

FIGS. 10A-E show resorbable component 250 in various views. Resorbablecomponent 250 may form a structural component for implant 210 and becomposed of structural resorbable material. Any of the resorbablematerials described in connection with implants 10, 110 can be used forresorbable component 250. Likewise, any of the materials and/or methodsused to compose frameworks 20, 120 of implants 10, 110 can be used toconstruct frame 220 of implant 210.

Resorbable component 250 of FIGS. 10A-E includes top and bottom surfaces252, 254, proximal and distal ends 256, 258, an implantation toolopening 266 in proximal end 256, and a bulleted nose 270 at distal end258. A vertical opening 260 is also formed in resorbable component 250through top and bottom surfaces 252, 254. In an embodiment, tool opening266 is threaded for engagement with a threaded portion of animplantation tool (not shown). In addition, opening 266 may extend intothe body of resorbable component 250 and open out into vertical opening260, such that opening 266 may form an injection port for injection of afusion material into the body of resorbable component 250. For instance,bone graft material may be injected into the body of resorbablecomponent 250 through opening 266 so that such bone graft material isable to interface with adjacent vertebral bodies through verticalopening 260 and affect fusion. Resorbable component 250 also hasengagement structures 264 that project outward from vertical opening260. Engagement structures 264 may interface with like engagementstructures (not shown) on frame 220 to secure resorbable component 250relative to frame 220.

In use, resorbable component 250 may be slid into engagement with frame220 through its lateral opening 228 so that engagement structures 264 ofresorbable component 250 engage with like engagement structures (notshown) on frame 220 to secure resorbable component 250 relative to frame220. Alternatively, these components could be pre-assembled by othermeans such as molding, packing, thermal assembly, 3D printing, orinterference fit. With resorbable component 250 in frame 220, it canprovide structural support for implant 210 and reinforce frame 220 (inparticular frame 220's top and bottom bone-contacting surfaces 222,224). Optionally, opening 266 in resorbable component 250 and opening236 in frame 220 can be used as injection ports to inject a fusionmaterial (e.g., bone graft) into resorbable component 250 for assistingwith the fusion process. Since openings 236, 266 align once resorbablecomponent 250 is positioned in frame 220, such openings 236, 266 may actas an injection port in the above-described manner. In this regard, theimplantation tool (not shown) used to connect with openings 236, 266 andinsert implant 210 into the intervertebral space may also have aninjection conduit for injecting fusion material into resorbablecomponent 250. Thus, the implantation tool (not shown) could threadablyconnect with at least one of openings 236, 266 and serve to alsoinjection fusion material into resorbable component 250 through itsinjection conduit.

Although not shown, it is also contemplated that top and bottom surfaces222, 224 of frame 220 and top and bottom surfaces 252, 254 of resorbablecomponent 250 may be tapered towards one another to create a lordoticimplant 210 for use in certain applications (e.g., in the lumbar spinewhere natural lordosis is present).

Implant 210, due to the thin top and bottom surfaces 222, 224 of frame220 and the structural support provided by resorbable component 250, mayalso act to increase graft loading over time. As an example, asresorbable component 250 resorbs and new bone is formed, the structuralstiffness of implant 210 may be reduced. In this case, where a bonegraft is used with implant 210 (e.g., in vertical opening 260 ofresorbable component 250 or elsewhere), such a decrease in stiffness canlead to increased graft loading over time and improve the fusionprocess.

In a particular embodiment, non-resorbable frame 220 may be composed ofa titanium alloy and resorbable component 250 of a resorbable materialwith mechanical properties similar to bone, such as CLM. In thisembodiment, non-resorbable frame 220 may occupy one-hundred percent(100%) of the overall surface area in contact with the vertebralendplates, while resorbable component 250 may occupy zero percent (0%).In this instance, the pores of non-resorbable frame 220 are not filledwith a resorbable material. Further, the volume of frame 220 may bethirty six percent (36%) of the overall volume of implant 210, while thevolume of resorbable component 250 may be sixty four percent (64%). Abenefit of this volume ratio is that the overall stiffness of the deviceis primarily dictated by resorbable component 250, which makes up amajority of the volume and also bears a majority of the service load inthe cephalad/caudad direction. Another benefit of this configuration, asit relates to implant 210, is that the radiopaque material (frame 220)has been located such that there is no obstruction for imaging thefusion mass from a lateral direction.

FIGS. 11A-E illustrate an implant 310, according to yet anotherembodiment of the present invention. Implant 310 comprises anon-resorbable, non-structural framework 320 that has a fluid channelconduit(s) 324 and a structural, resorbable component 350 positionedaround framework 320. Due to the differences from previous embodiments,certain like numerals refer to like elements, but no consistentnumbering scale is used in this embodiment.

As shown in FIGS. 12A-E, framework 320 of implant 310 has a main body322 that includes at least one conduit 324 therein. Framework 320 alsohas proximal and distal ends 330, 332, an injection port 334 at proximalend 330, and a vertical opening 336 through main body 322. Injectionport 334 doubles as an implantation tool opening, and thus, it isthreaded in an embodiment to engage with a threaded portion of animplantation tool (not shown). Injection port 334 is fluidly connectedto conduit 324 so that fluid can be injected into port 334 and travelinto and through conduit 324. In an embodiment, conduit 324 traversessubstantially an entire perimeter of main body 322 of framework 320.Framework 320 also includes an enlarged portion 340 forming a step atits proximal end 330 and conduit 324 may traverse enlarged portion 340until it intersects with and opens out into injection port 334. In aparticular embodiment, main body 322 is closed beyond injection port 334so that, as fluid is forced into injection port 334, it flows from port334 and into conduit 324.

In another embodiment, injection port 334 and conduit 324 can includeany of the fittings and/or flow channels described in connection withApplicant's U.S. Application Ser. No. 62/103,270, now U.S. patentapplication Ser. No. 14/994,697, which are hereby incorporated byreference herein. The '270 application was attached as Exhibit B to the'146 Provisional. As an example, FIGS. 5A-E of the '270 applicationdepict an implant 410 with a threaded passage 424 and a flow channel 428in fluid communication therewith. The structure of threaded passage 424and flow channel 428 could be utilized in connection with framework 320herein. Indeed, although not expressly described in this disclosure, itis to be appreciated that any of the flow channels (including multipleflow channels), fittings, passages therefor, and other structures of theimplants taught in the '270 Applicant can be used with framework 320and/or resorbable component 350 herein. Applicant provides certainexamples of the structures from the '270 application that could be usedherein, but such examples are not to be taken as limiting and it shouldbe recognized that any of the principles of the '270 application areusable with implant 310.

Framework 320 of implant 310 also has a plurality of cylinders 326projecting outward from main body 322, which terminate in holes 327. Asdescribed in more detail below, cylinders 326 extend through resorbablecomponent 350 so that holes 327 are open to the exterior of implant 310,much like the holes described in the '270 application. As shown in crosssection in FIG. 12E, cylinders 326 each have a conduit 338 that is influid communication with conduit 324 of main body 322. Thus, fluid canflow from conduit 324, into each of conduits 338 of cylinders 326, andultimately to the exterior of implant 310 via holes 327. As such, it ispossible to inject fluid into implant 310 and have the fluid coat theexterior of implant 310. As described in the '270 application, the fluidinjected into implant 310 may be a biologic material, a therapeuticmaterial, a bone cement, bone-growth promoting material, Bone MarrowAspirate, antimicrobial material, bone morphogenic proteins (“BMP”),stem cells, solutions to assist in the resorption process,tissue-targeted glycosaminoglycans, or any other like material.

Resorbable component 350, one side of which is shown in FIGS. 13A-E,includes top and bottom surfaces 352, 354, proximal and distal ends 356,358, a vertical opening 360, and teeth 362 formed on top surface 352.Resorbable component 350 may be composed of any of the resorbablematerials discussed in connection with the previous implants 10, 110,210 and, in an embodiment, is a flowable material that is embeddedwithin framework 320 during manufacturing. In this regard, framework 320and its projecting cylinders 326 can act as a scaffold to retainresorbable component 350 in connection with framework 320. Additionally,framework 320, in its capacity as a scaffold, can provide support toresorbable component 350 so that component 350 does not crack orfracture during implantation. Indeed, resorbable materials are, in someexisting implants, susceptible to fracture or cracking duringimplantation. As an example, allograft bone is often brittle duringimplantation.

Resorbable component 350 also has a series of holes 368 arranged toalign with projecting cylinders 326 of framework 320 and allow fluid toexit holes 327 of such cylinders 326. Fluid exiting holes 327 ofcylinders 326 (and thus holes 368 of resorbable component 350) may actto coat top surface 352 of resorbable component 350 and assist with theresorption and/or fusion process. Resorbable component 350 furtherincludes, at its proximal end 356, a stepped portion 364 shaped andarranged to engage with enlarged portion 340 of framework 320. Althoughnot shown, a second resorbable component 350 identical to that shown inFIGS. 13A-E is usable with implant 310 on an opposing side of implant310.

While not described above, it is also contemplated that conduit 324 offramework 320 may, in addition to or as a substitute to directing fluidto an exterior of implant 310, also be arranged to direct fluid to alocation fully enclosed within resorbable component 350. Such a conduitwould be beneficial to deliver fluid (e.g., a resorptive-enhancingfluid) to a location within resorbable component 350. It is also thecase that conduit 324 (or multiple conduits if included) may directfluid to other exterior parts of implant 310, for example the sides orproximal and/or distal ends of implant 310. In addition, if multipleconduits 324 are included with framework 320, different materials can bedirected to different portions of implant 310. These types of conduitsare disclosed in more detail in the '270 application.

FIGS. 14A-E depict an implant 410, according to another embodiment ofthe present invention. Implant 410 includes a non-structural,non-resorbable framework 420 and a structural, resorbable component 450positioned within and/or around framework 420. Due to the differencesfrom previous embodiments, certain like numerals refer to like elements,but no consistent numbering scale is used in this embodiment.

As shown in FIGS. 15A-E, framework 420 has first and second ring members422, 424 and struts 426 that connect ring members 422, 424. Struts 426terminate in proximal and distal end plates 428, 430 arranged onframework 420. In an embodiment, proximal end plate 428 includes animplantation tool opening 432 that is optionally threaded for engagementwith a threaded portion of an implantation tool (not shown). Framework420, via its ring members 422, 424, struts 426, and end plates 428, 430,provides a scaffold for embedding resorbable component 450 withinframework 420. Although framework 420 is non-structural, in the sensethat it does not support post-surgical loads directly, it providesstrength and rigidity to implant 410 and resorbable component 450thereof.

Resorbable component 450 is shown in FIGS. 16A-E and includes a mainbody 451 having top and bottom bone-contacting surfaces 452, 454,proximal and distal ends 456, 458, an implantation tool opening 466 atproximal end 456, and a vertical opening 460 formed through main body451. As with the previous embodiments, implantation tool opening 466 mayor may not be threaded for engagement with a threaded portion of animplantation tool (not shown). Additionally, opening 466 may be in fluidcommunication with vertical opening 460 so that a fusion or anotherbiologic material can be injected into opening 460 via a tool. Such atool is disclosed, for example, in the '270 application and it isexpressly contemplated that any tool of the '270 application is usablewith implant 410, as well as any of the previous implants.

Resorbable component 450 also includes teeth 462 on its top and bottomsurfaces 452, 454, and may be composed of any of the resorbablematerials hereinbefore described. In an embodiment, resorbable component450 is preassembled on framework 420 at the point of manufacture andprovides structural support for implant 410 in that it is capable ofsupporting the post-surgical loads borne on implant 410 after insertioninto a patient. This type of implant configuration is particularlyuseful when the resorbable material is strong but brittle, as spinalimplants are often impacted into place and must be able to withstandimpact loads without fracturing or becoming damaged. With implant 410,impaction loads are borne by framework 420 (e.g., at tool opening432/proximal end plate 428), and thus, the resorbable material ofresorbable component 450 is safe from fracture and/or other damageduring implantation. Resorbable component 450 also resists fracture dueto the support provided by framework 420 in its capacity as a scaffold.

In a particular embodiment, it is possible to modify framework 450 toalso increase or decrease the overall stiffness of implant 410. As anexample, the components of framework 420 may be made thicker or thinnerin certain locations (e.g., struts 426 and rings 422, 424) to increaseor decrease the overall rigidity of framework 420, and thus implant 410.Different thickness frameworks 420, and Finite Element Analyses relatedthereto, are shown in FIGS. 17-18. As reflected in those figures, adifferent stiffness is realized for implant 410 between the thicker andthinner frameworks 420.

FIGS. 19-23 depict various images of prototypes of frameworks 20, 120,220, 320, 420 of implants 10, 110, 210, 310, 410. It is to be understoodthat any of these prototypes can be constructed using an additivemanufacturing process, as hereinbefore disclosed. Additionally, each ofthe frameworks may be composed of any of the materials discussed inconnection with any of the above-described frameworks. Further, othermanufacturing methods such as injection molding processes may be used toconstruct frameworks 20, 120, 220, 320, 420. Thus, a variety ofmaterials and manufacturing methods may be utilized to create frameworks20, 120, 220, 320, 420. Certain particular features of the variousprototypes will now be discussed.

Referring to all of the prototypes of FIGS. 19-23, it is seen that aporous and/or roughened layer or surface coating may be used on all,substantially all, or a majority of the exposed surfaces of frameworks20, 120, 220, 320, 420. Such a coating could enhance the resorptiveand/or fusion characteristics of a particular framework, make it moreamenable to connection with a particular resorbable component ormaterial, or simply increase the framework's resistance to migration inthe intervertebral space once implanted.

Referring to the prototype of framework 220 of FIG. 21, it is also seenthat top and bottom bone-contacting surfaces 222, 224 are highly porousand thin. Such surfaces 222, 224, as described above, are structurallysupported by resorbable component 250. Additionally, in the image of theprototype of framework 220, it is shown that framework 220 can havemultiple lateral openings for receiving resorbable component 250,instead of only a single lateral opening 228.

Turning to the prototype of framework 420 of FIG. 23, it is shown in oneof the prototypes (left) that a variety of differently-sized struts maybe used in framework 420. As an example, smaller struts may traversebetween distal end plate 430 and second ring 424 and between proximalend plate 428 and first ring 422. One or more side struts may also beused on framework 420, as shown. Such side struts may be bowed and beconnected to proximal end plate 428, first ring 422, second ring 424,and finally distal end plate 430. These additional struts may provideyet additional stiffness to implant 410 and/or act as a further scaffoldfor resorbable component 450.

A surgical kit is also contemplated within the present invention. Due tothe inability for many of the known resorbable materials to be properlysterilized via autoclave without being rendered unusable, it is expectedthat at least any of the resorbable components described above may beprovided in a sterile package in the kit. This packaging could encloseeither the entire finished implant (resorbable and non-resorbablecomponents), or just the resorbable component with the intent toassemble intraoperatively. Indeed, although many of the implantsdiscussed above are described as being assembled upon manufacturing, itis contemplated that resorbable and non-resorbable components of theabove implants may be assembled in the operating room or in-situ. Thein-situ assembly process could include first implanting thenon-resorbable component into the spine, and then injecting or flowing acurable resorbable component through and/or around the non-resorbableportion/framework within the disc space. The resorbable component couldthen be allowed to cure/harden, at which point the implant may be leftimplanted for purposes of resorption of the resorbable material andfusion of the vertebral bodies. It is contemplated that such a processis possible with any of frameworks 20, 120, 220, 320, 420 of implants10, 110, 210, 310, 410.

The surgical kit may also include implants 10, 110, 210, 310, 410 ofdifferent sizes for use with different patients, and tools for theimplantation of such implants. An example of such a tool is the tooldisclosed in the '270 application, which is usable to insert some of theimplants described previously and/or inject a biologic material intosuch implants.

Additionally, while no particular surgical approach has been discussedabove in connection with implants 10, 110, 210, 310, 410, and suchimplants are not limited to any particular surgical approach or use, itis contemplated that certain of the above implants may be moreparticularly suited for certain surgical applications. As an example,implants 10, 110 may be suited for use as ALIF implants (anterior lumbarinterbody fusion), implant 210 may be suited for use as a PLIF implant(posterior lumbar interbody fusion), and implants 310, 410 may be suitedfor use as DLIF implants (direct lateral interbody fusion). Of course,the foregoing implants may be suitable for use in other areas of thespine and along different surgical approaches (e.g., anterolateral,transforaminal, etc.). As an example, the features and structures of theabove implants may be suitable for use in cervical applications. Theabove-described uses and surgical approaches are therefore not to betaken as limiting and are merely exemplary. Likewise, the implants shownin the figures are merely examples of those which can be createdaccording to the present invention. It is contemplated that otherimplant shapes/configurations can be made in accordance with the presentinvention.

In the devices shown in the figures, particular structures are shown asbeing adapted for use in the implantation of an implant according to thepresent invention. The invention also contemplates the use of anyalternative structures for such purposes, including structures havingdifferent lengths, shapes, and/or configurations. For instance, althoughthreaded connection mechanisms are taught herein (e.g., for insertion ofthe foregoing implants with an implantation tool), it is equally thecase that non-threaded connection mechanisms can be used. For instance,a bayonetted connection, press-fit connection acting through dimensionalinterferences, luer connection, or other like locking connection may beused to implant any of implants 10, 110, 210, 310, 410 into theintervertebral space via an implantation tool with a like connection.This is particularly the case for implant 310 which, although it has athreaded, recessed opening 334, may alternatively include any of theprojecting luer fittings disclosed in the '270 application. Implant 310is, of course, merely used as an example.

Further modifications and variants of the foregoing implants 10, 110,210, 310, 410 are also contemplated. For instance, although certain ofimplants 10, 110, 210, 310, 410 may not be described above as includinglordotic bone-contacting surfaces, such a feature is expresslycontemplated with each of implants 10, 110, 210, 310, 410 as an option.In particular, it is contemplated that any of implants 10, 110, 210,310, 410 may include lordotic surfaces (e.g., surfaces that tapertowards one another) to accommodate natural lordosis that is present incertain areas of the spine. Some of implants 10, 110, 210, 310, 410 areshown in the figures with a lordotic taper, although that feature maynot be expressly discussed above.

In addition, while discussed somewhat in connection with implant 310, itis contemplated that such implant 310 may include multiple fluidconduits instead of the single conduit 324 shown in the figures. Suchconduits may be fluidly isolated from one another to allow differentfluids to be transferred to different parts of the implant, or theconduits may be fluidly connected. Additionally, certain fluid conduitsmay lead to areas wholly encompassed in resorbable component 350 insteadof opening out to an exterior of implant 310, as described above. Someof these and other features are taught in the '270 application, and itis to be understood that such features and/or structures are usable withimplant 310.

In a further example, although implant 110 is described as using aparticular bone anchor 174, it is contemplated that framework 120 andresorbable component 150 may be provided with more traditionalbone-anchor features. For instance, framework 120 and resorbablecomponent 150 may be provided with threaded holes for engaging withtraditional threaded bone screws. Such holes may be arrangedsubstantially as shown in connection with keyed openings 144, 166 (e.g.,the holes may number four (4) in total, and diverge outward so that bonescrews are directed up/down into the vertebral bodies, and in an outwarddirection). If bone-screw holes are included, certain anti-backoutfeatures might also be provided. For instance, a movable protrusion maybe provided in each hole that automatically moves in response to a bonescrew being inserted into the hole, and snaps back once the bone screwhas passed the protrusion so as to cover the particular bone screw. Sucha mechanism could prevent backout of screws inserted into implant 110.Other anti-backout mechanisms might also be used, such as traditional“man-hole covers,” which are attached to the implant after the bonescrews have been inserted and act to cover one or more of the bonescrews.

In further variants, it is contemplated that any of implants 10, 110,210, 310, 410 may utilize the following surface area and/or volumeranges for the non-resorbable and resorbable components thereof:

Surface Area in Contact with Endplates Volume Minimum Maximum MinimumMaximum Non-resorbable 10% 100% 10% 80% Resorbable  0%  90% 20% 90%

As yet another example, any of the resorbable components above may becombined with biologics and/or anti-infectives, including but notlimited to bone marrow, blood, growth factors, proteins, peptides CAGs,antimicrobials, and/or antibiotics.

Although the invention herein has been described with reference toparticular embodiments, it is to be understood that these embodimentsare merely illustrative of the principles and applications of thepresent invention. It is therefore to be understood that numerousmodifications may be made to the illustrative embodiments and that otherarrangements may be devised without departing from the spirit and scopeof the present invention as defined by the appended claims.

It will also be appreciated that the various dependent claims and thefeatures set forth therein can be combined in different ways thanpresented in the initial claims. In particular, any feature of anydependent claim may be combined with a feature of another independent ordependent claim, to the extent technologically feasible, as if theclaims were written with multiple dependencies to reflect such differentcombinations. It will further be appreciated that the features describedin connection with individual embodiments may be shared with others ofthe described embodiments.

The invention claimed is:
 1. An implant sized and adapted for insertioninto an intervertebral space between adjacent vertebral bodiescomprising: a non-resorbable, structural framework having top and bottombone-contacting surfaces and a plurality of struts defining geometricopenings between the top and bottom surfaces, the struts providingstructural support for the framework, wherein the framework includes aplurality of support columns extending between proximal and distal endsof the framework, the plurality of support columns being spaced apartfrom each other to define vertical openings in the framework; and aresorbable material component within and/or around the framework forresorption and formation of new bone to fuse the vertebral bodiestogether, at least a portion of the framework being interposed betweenthe resorbable material component, the resorbable material componenthaving top and bottom bone-contacting surfaces arranged to contactvertebral endplates over a contact surface area sufficient to reducepeak stresses between the framework and the vertebral bodies to reduceor eliminate subsidence of the framework into the vertebral bodies. 2.An implant according to claim 1, wherein the framework defines at leastone opening extending through its top and bottom surfaces, and theresorbable material component is positioned within the at least oneopening so as to encourage new bone formation through the at least oneopening.
 3. An implant according to claim 1, wherein the top and bottombone-contacting surfaces of the resorbable material component areconfigured to support post-surgical loads experienced after implantationof the implant.
 4. An implant according to claim 1, wherein theplurality of support columns extend longitudinally from the proximal endto the distal end of the framework.
 5. An implant according to claim 1,wherein the plurality of struts defining geometric openings at leastpartially form each support column.
 6. An implant according to claim 1,wherein the resorbable material component includes at least one verticalopening extending through a main body of the resorbable materialcomponent.
 7. An implant according to claim 1, wherein the implantfurther comprises a bone anchor having a bladed portion and a keyedinterconnection portion, and the framework includes at least one keyedopening sized and shaped to receive the keyed interconnection portion.8. An implant according to claim 7, wherein once engaged with theframework, the bladed portion of the bone anchor extends outwards fromeither the top or bottom surface of the framework.
 9. An implantaccording to claim 7, wherein the resorbable material component furthercomprises a keyed interconnection portion that is substantially the sameshape as the keyed interconnection portion of the framework, and whereinthe keyed interconnection portions of the resorbable material componentand the framework, respectively, are aligned to allow engagement of thebone anchor with the implant.
 10. An implant according to claim 1,wherein the resorbable material component is composed of a materialselected from the group consisting of bioactive glass, bone,polylactides, collagen, magnesium alloy, or a Cross-LinkedMicrostructure (CLM) bioglass material.
 11. A method of reducingsubsidence of an implant into bone comprising: providing an implanthaving a non-resorbable structural framework and a resorbable structuralcomponent positioned within and/or around the framework, at least aportion of the framework being interposed between the resorbablestructural component; implanting the framework between first and secondadjacent vertebral bodies so that top and bottom surfaces of theframework contact vertebral endplates of the first and second vertebralbodies; and implanting the resorbable component between the first andsecond adjacent vertebral bodies so that top and bottom surfaces of theresorbable component contact the vertebral endplates, wherein the topand bottom surfaces of the resorbable component contact the vertebralendplates over a contact surface area sufficient to reduce peak stressesbetween the framework and the vertebral bodies by an amount effective toeliminate or reduce subsidence of the framework into the vertebralbodies.
 12. A method of reducing subsidence according to claim 11,wherein in the absence of the resorbable component, peak stressesbetween the framework and the vertebral bodies is above a stressrequired for the vertebral endplates to fail.
 13. A method of reducingsubsidence according to claim 11, wherein the resorbable componentreduces peak stresses between the framework and the vertebral bodies byabout 40-80%.
 14. A method of reducing subsidence according to claim 11,wherein the contact surface area is between about 30-70% of an overallcontact surface area of the implant in contact with the vertebralendplates.
 15. A method of reducing subsidence according to claim 11,wherein the resorbable component occupies about 50-80% of an overallvolume of the implant, and the framework occupies about 20-50% of theoverall volume of the implant.
 16. An implant sized and adapted forinsertion into an intervertebral space between adjacent vertebral bodiescomprising: a non-resorbable, structural framework having top and bottombone-contacting surfaces and a plurality of struts defining geometricopenings between the top and bottom surfaces, the struts providingstructural support for the framework; and a resorbable materialcomponent within and/or around the framework for resorption andformation of new bone to fuse the vertebral bodies together, at least aportion of the framework being interposed between the resorbablematerial component, wherein the resorbable material has top and bottombone-contacting surfaces, and the top and bottom surfaces of theresorbable component are arranged to contact the vertebral endplatesover a contact surface area sufficient to reduce peak stresses betweenthe framework and the vertebral bodies by an amount effective to reduceor eliminate subsidence of the framework into the vertebral bodies. 17.An implant as claimed in claim 16, wherein the contact surface area isbetween about 30-70% of an overall contact surface area of the implantin contact with the vertebral endplates.
 18. An implant as claimed inclaim 16, wherein the resorbable component reduces peak stresses betweenthe framework and the vertebral bodies by about 40-80%.
 19. An implantas claimed in claim 16, wherein in the absence of the resorbablecomponent, peak stresses between the framework and the vertebral bodiesis above a stress required for the vertebral endplates to fail.